Hi, can anyone advise me how to open up this tap to replace the washer? I thought unscrewing the larger nut would do it, but it turns in both directions without either loosening or tightening. I tried loosening the smaller nut, but it wouldn't move (I was reluctant to use too much force, as I wasn't sure it was supposed to undo). I can't remove the tap handle either - I presume the white cap is meant to unscrew, but I can't shift it. Any advice would be greatly appreciated!!